Optical properties and electronic structures of semiconductors with screened-exchange LDA

Asahi, Ryoji; Mannstadt, W.; Freeman, Arthur J

doi:10.1103/physrevb.59.7486

Cited by 173 publications

(109 citation statements)

References 44 publications

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“…(11)) with a non-local potential is solved. For semiconductors and insulators this leads to a much improved description of band gaps [27,66,115,116,[118][119][120]. From the point of perturbation theory this is again beneficial since the perturbation required by the GW (or eventually the true) selfenergy is smaller.…”

Section: Discussionmentioning

confidence: 99%

“…The factor α in front of the Hartree-Fock exact-exchange term is equivalent to a constant static screening function. Alternatively a more complex screening function can be chosen as in the screenedexchange (sX-LDA) approach [17,28,115,116], the -GKS Σ scheme [117] or the Heyd-Scuseria-Ernzerhof (HSE) functional [25][26][27]. An appealing feature of the hy- 18 Some hybrid schemes introduce additional parameters for mixing different portions of the local-spin density (LSD) functional with GGA exchange and correlation in the DFT xc E term [21].…”

Section: Discussionmentioning

confidence: 99%

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Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Rinke¹,

Qteish

Neugebauer

et al. 2008

Physica Status Solidi (b)

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1 Introduction Density functional theory (DFT) has contributed significantly to our present understanding of a wide range of materials and their properties. As quantummechanical theory of the density and the total energy, it provides an atomistic description from first principles and is, in the local-density or generalized gradient approximation (LDA and GGA), applicable to polyatomic systems containing up to several thousand atoms. However, a combination of three factors limits the applicability of LDA and GGA to a range of important materials and interesting phenomena. They are approximate (jellium-based) exchange-correlation functionals, which suffer from incomplete cancellation of artificial self-interaction and lack the discontinuity of the exchange-correlation potential with respect to the number of electrons. As a consequence the Kohn-Sham (KS) single-particle eigenvalue band gap for semiconductors and insulators underestimates the quasiparticle band gap as measured by the difference of ionisation energy (via photoemission spectroscopy (PES)) and electron affinity (via inverse PES (IPES)). This reduces the predictive power for materials whose band gap is not know from experiment and poses a problem for calculations

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Rinke¹,

Qteish

Neugebauer

et al. 2008

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

“…Because LDA underestimates the oxide band gaps and may give incorrect energy location of the states of different cations in the conduction band of multicomponent materials, we also employed the self-consistent screenedexchange LDA (sX-LDA) method [20,[24][25][26][27] for more accurate description of the band gap values and the valence/conduction band states of the twelve complex oxides. For the sX-LDA calculations, cutoff for the plane wave basis was 10.2 Ry and summations over the Brillouin zone were carried out using at least 14 special k points in the irreducible wedge.…”

Section: Methods and Approximationsmentioning

confidence: 99%

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Murat

Medvedeva

2012

Phys. Rev. B

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The structural, electronic, and optical properties of twelve multicomponent oxides with layered structure, RAMO4, where R 3+ =In or Sc; A 3+ =Al or Ga; and M 2+ =Ca, Cd, Mg, or Zn, are investigated using first-principles density functional approach. The compositional complexity of RAMO4 leads to a wide range of band gap values varying from 2.45 eV for InGaCdO4 to 6.29 eV for ScAlMgO4 as obtained from our self-consistent screened-exchange local density approximation calculations. Strikingly, despite the different band gaps in the oxide constituents, namely, 2-4 eV in CdO, In2O3, or ZnO; 5-6 eV for Ga2O3 or Sc2O3; and 7-9 eV in CaO, MgO, or Al2O3, the bottom of the conduction band in the multicomponent oxides is formed from the s-states of all cations and their neighboring oxygen p-states. We show that the hybrid nature of the conduction band in multicomponent oxides originates from the unusual five-fold atomic coordination of A 3+ and M 2+ cations which enables the interaction between the spatially-spread s-orbitals of adjacent cations via shared oxygen atoms. The effect of the local atomic coordination on the band gap, the electron effective mass, the orbital composition of the conduction band, and the expected (an)isotropic character of the electron transport in layered RAMO4 is thoroughly discussed.

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“…In our defect calculations, in addition to the bandgap correction via the screened-exchanged LDA method [38][39][40][41], we also address the band-edge and the finite-size supercell errors in the defect calculations. We employ the correction methods proposed by Lany and Zunger [42], namely, (i) shifting of shallow levels with the corresponding band edges of the host; (ii) band-filling correction; (iii) potential-alignment correction for supercells with charged defects; and (iv) image charge correction for charged defects via simplified Makov-Payne scheme [42].…”

Section: Approachmentioning

confidence: 99%

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

Murat

Medvedeva

2012

Phys. Rev. B

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The formation and distribution of oxygen vacancy in layered multicomponent InAM O4 oxides with A 3+ =Al or Ga, and M 2+ =Ca or Zn, and in the corresponding binary oxide constituents is investigated using first-principles density functional calculations. Comparing the calculated formation energies of the oxygen defect at six different site locations within the structurally and chemically distinct layers of InAM O4 oxides, we find that the vacancy distribution is significantly affected not only by the strength of the metal-oxygen bonding, but also by the cation's ability to adjust to anisotropic oxygen environment created by the vacancy. In particular, the tendency of Zn, Ga, and Al atoms to form stable structures with low oxygen coordination, results in nearly identical vacancy concentrations in the InO1.5 and GaZnO2.5 layers in InGaZnO4, and only an order of magnitude lower concentration in the AlZnO2.5 layer as compared to the one in the InO1.5 layer in InAlZnO4. The presence of two light metal constituents in the InAlCaO4 along with Ca failure to form a stable fourfold coordination as revealed by its negligible relaxation near the defect, leads to a strong preference of the oxygen vacancy to be in the InO1.5 layer. Based on the results obtained, we derive general rules on the role of chemical composition, local coordination, and atomic relaxation in the defect formation and propose an alternative light-metal oxide as a promising constituent of multicomponent functional materials with tunable properties.

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Optical properties and electronic structures of semiconductors with screened-exchange LDA

Cited by 173 publications

References 44 publications

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

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